Officers investigating an incident in Taunton are asking any witnesses who have not yet contacted the police to come forward.
Police were called to a barbers in the East Reach area at approximately 1.10pm on Friday 23 April.
A man had reportedly made racially-aggravated comments against staff inside the premises and demanded money from the till. Having been ejected from the premises without taking any money, he then drove off in a silver Vauxhall Zafira.
Shortly afterwards he returned and with a knife injured an employee outside the shop. The victim was taken to hospital for treatment and released later that same day.
A 32-year-old man was arrested and has been released under investigation.
Enquiries, including reviewing CCTV footage, continue.
Anyone who witnessed what happened inside or outside the premises is asked to contact us online or via 101, quoting reference number 5221087144.